ml350 Very Bad Mpg

[hamazz]

Got an issue with my wife w163 ml350,
The range on the tank is about 200miles in normal driving within london before the light come on, calculating it online come out at about 13mpg which is very low. I know city driving drops the mpg a bit, but this is worse than our v8 5.7 hemi dodge ram.

Wifes said its been like that for a few months, on a recent road trip to europe we were averaging about 380miles per tank and that was doing about 3000rpm 100mph+ in germany. for about 10 days, once back in london the tank range dropped straight down to 200-210miles.

On a recent run from London to Birmingham and back on the same day, the range was also 200miles on the tank.

Put a scanner on the car, and came up with codes P2017 and P2086, "Self adaptation of mixture formation (right/left bank) of cylinders is at limit value at idle speed - too rich"

Somethings wrong not sure where to start, EGR cleaning, MAF, or what, any tips so that we can get the mpg to a normal level, as the car is obviously running very rich.

Hamazz

 

[Auto-mobile]

Based on what you have said I'd be going with a maf, Bosch or pierburg.

 

[Bobby Dazzler]

MAF would be first on my list of things to replace.

 

[hamazz]

yeah thats what i was going to do first, but something else came up today, the battery indicator came on, on way home, then the satnav started flashing and lights dimming, the abs,pas, bas/esp srs etc came on aswell, was about 1 min from home, so parked it and hooked/jumped it off our other merc, all the lights all went out, as soon as i removed the jump leads all the lights came back one.

guessing alternator or bad battery, will have to measure it in the morning, would this also affect the mpg at all? if the battery was dodgy and not providing enough current to spark correctly resulting in rich running, or would it have thrown another code?

Hamazz

 

[Auto-mobile]

I'd say you now have two faults.

 

[hamazz]

sorted out the battery issue, alternator was gone, and rather than replace just the voltage regulator done the whole unit as is about 10 years old.

on the fuel issue, changed the MAF for a new one, not bosch brand, the fuel consumption is still the same as before, only does about 200miles per tank, so no difference by changing the maf, any other ideas or tips where to look next

hamazz

 

[jibcl500]

sorted out the battery issue, alternator was gone, and rather than replace just the voltage regulator done the whole unit as is about 10 years old.

on the fuel issue, changed the MAF for a new one, not bosch brand, the fuel consumption is still the same as before, only does about 200miles per tank, so no difference by changing the maf, any other ideas or tips where to look next

hamazz

Maf needs to be a gen item not aftermarket, Id suggest you get the ML on star digs and go from there.

jib

 

[hamazz]

changed the maf and still have the same issue, the other codes have cleared,
got a trip computer that i installed on the car, to try and see the mpg usage, the range, normally starts at about 350miles when tank is full, but the drop rate is very fast, it just ticks away, a normal 1mile distance will drop about 5 miles or more on the range.

any other ideas guys, im trying to find a local garage that can do a mb diag check to see if there is anything else wrong.

someone mentioned a terraclean to clean the whole intake, egr, injectors etc in one go, does anyone know if it is worth it, its about £100 or so. not sure if it is worth spending the money on it.

hamazz

 

[hamazz]

anyone know what the proper Bosch maf number should be on the ml350? as i think maybe the existing might not have been original ?

hamazz

 

[gIzzE]

Official Urban figures is 14mpg.
The light comes on at 70 litres, most fill ups for me on my W163 saw 72 litres go in after the light had come on.

At 14mpg that would give you 220 miles between fill ups.


I don't think you have a problem personally, they are just seriously thirsty. Mine was a mapped 270cdi with EGR bypass and decatted that could see 500 miles on a run, which was 32mpg, however, just short journeys round town would see only 320 miles which was only 20mpg.

 

[landondonovan]

Go for a gen MAF. What's the status of your alternator?

 

[harolddominguez]

wohoo.. this was awesome!